PIPE FITTINGS

Fittings are fabricated pieces of pipe that

are used to make changes of direction (elbow),
branch from a main pipe (tee), or make a
reduction in line size (reducer) connections.
A pipe fitting does one or more of the
following:
• Changes the direction of the flow—elbows, tee.
• Changes the size of the pipe—reducers, reducing
tees, reducing couplings.
• Joins together pipe—flanges, couplings.
• Dismantles pipe—flanges, unions.
• Isolates the flow — Spectacle blinds, Spades and
Spacers
• Reinforces branch connections—weldolets,
threadolets,sockolets.
TYPES OF FITTINGS
Based on end Fittings Types
connection
Socket weld Fittings Elbows 90°(LR & SR)Elb &
45°Elb
screwed end Fittings Mitered Bends 1,2,3 or 4 weld miters
Beveled end Fittings Tees Equal, Reducing
Flanged end Fittings Cross Equal, Reducing
Spigot socket Fittings Caps
Buttress end Fittings Reducers Concentric & Eccentric
Stubends Long, Short
Couplings Full, Half & Reducing
Swage nipples Concentric & Eccentric
Unions
Special Weldolet, Sockolet,
fittings(olets) Thredolet,Elbolet,Latro
let, Sweepolet etc..
 Elbows:
1. 90o Elbows: •Long Radius – 1.5D
•Short Radius – 1D
2. 45o Elbows: These are of 1.5 D radius.
Note: 1.For large diameter piping, bends
are fabricated by profile cutting of
pipes & are called Mitre bends.
2.Mitre bends with 2,3 & 4 piece
construction can be made.
Tees: Tees are used for branching off.
Thumb Rule – To get available sizes of reducing tee is,
Divide the major diameter by 2 & consider the next lower size.
Cross: To reduce the inventory, it is preferred to use tees except where space
is restricted.
Unions: Used in low pressure piping where dismantling of pipe is required
more often, as an alternative to flange.
Returns: This is mainly used in heating coils, heat exchangers etc.
Available with 1.5D & 1D radius.
Reducers:
Concentric – Used when center lines of small & large pipe are to be
maintained same.
Eccentric – When one of the outside surfaces of pipelines are to be
maintained same.
There are no eccentric reducers in socket weld fittings & swage nipples
are used for such services.
Swage nipples: Similar to reducer but used to connect but welded pipe
to smaller screwed or socket welded pipes.
Concentric & Eccentric reducers are available.

Coupling:
Types – 1.Full Coupling – to connect small bore screwed
and socket-weld pipe to large-bore pipe
headers.
2.Half coupling – for branch connection.
3.Reducing coupling – for size reduction.
•the coupling is also used extensively where instrument
connections are required.
Special Fittings:
 Weldolet – for Butt weld branch connection.
 Sockolet– for Socket weld branch connection.
 Threadolet– for Threaded branch connection.
 Elbolet – for branch connection on elbow.
 Sweepolet – is integrally reinforced butt weld branch connection.
 Latrolet - for branch connection at an angle.
 Nipolet
Stub Ends:
To reduce the cost of piping these are used with backing flanges for flange
joints when exotic materials used in piping.
 ASME B16.9 specifies 2 type of stub ends
• Long stub ends
• Short Stub ends
 The Length of stub ends as per MSS SP 43 is the same as that of
short stub stub ends.
 MSS SP 43 specifies 2 classes
Class A – with radius
Class B – without radius – can be used with slip-on flanges.
THE STUB-IN:
Another type of fitting used to make branch connections
use of the stub-in is limited by the pressure, temperature, and
commodity within a pipe.
 In such conditions special reinforcement may be necessary to
prevent the branch from separating from the header.

Caps

Nipples

WELD CAP : is used to seal an open end of pipe.

PLUG : Plugs are manufactured for screwed fittings with
male threads and are screwed into the end of a pipe to
create a seal.
NIPPLES : Small lengths of pipe used between fittings to
facilitate the assembly of screwed & socket-
Dimensional Standards Covering End Connections
of Components
End Connection Joint Type ASME Standard Size
Weld end (WE) Butt weld ASME B16.25 All sizes
Plain end (PE) Socket weld ASME B16.11 4 in. and
below
Threaded (Thd) Screwed ASME B1.20.1 4 in. and
DIMENSIONAL STANDARDS FOR PIPING COMPONENTS
below
Type of component Function Butt-Weld Threaded-Socket-
Ends(1/2–48 Weld Ends (1/2–4
in.) in.)
90° LR Elbow Change Direction ASME B16.9 ASME B16.11
90° SR Elbow Change Direction ASME Not applicable
B16.28
45° ell. & 180 ° Change Direction ASME B16.9 ASME B16.11
Returns
Equal Tee Change Direction ASME B16.9 ASME B16.11
Reducing Tee Change dirn. & size ASME B16.9 ASME B16.11
Reducers(Conc. & Change Size ASME B16.9 ASME B16.11
Eccen.)
Reinforced Branch Change dirn. & size Manufactur Manufacturer’s
(O’let) er’s standard
standard